3of3Belinda Leong and Michael Suas of b. PatisseriesPhoto: Jen Fedrizzi / Special to The Chronicle

At B. Patisserie, Belinda Leong, Michel Suas and their team captivate mobs of local regulars and far-flung visitors with cakes, tarts, laminated pastries, cookies and breads stacked on a long marble counter in their James Beard Award-winning Pacific Heights shop.

A tired food-writing truism often lurks in the discussion around high-profile bakeries like B. Patisserie: savory cooking is an art, but baking is a science. Physics, chemistry and biology have ruled everything we have ever eaten since before we invented kitchens, and savory cooking is no different from baking in its intimate dependence on science. Whether a baker fits the mold of Suas, an analytically minded technician, or Leong, a self-taught virtuoso who seldom measures anything, the principles that differentiate their craft from that of line cooks and savory chefs are not scientific; they’re architectural.

Leong and Suas combine the sensitivity of prodding hands with the consistency of precision techniques to lead their talented crew in constructing delicious cathedrals from shapeless powders, pastes and liquids. Here are the blueprints they’ve created for three of their landmark offerings.

Crispiness and crunchiness emerge from tangled mishmashes of sugar, carbs or proteins dehydrated to form an inflexible glass. These locked-up structures are too brittle to bend, so they fracture when bitten. Crispiness is the sensation of cracking a thin layer of one of these edible glasses. Crunchiness is the chaos that happens when our teeth crash through a stack of crispy layers. The 3-D topography of B. Patisserie’s granola spans both ends of this shattering spectrum, plus the gray area between.

Leong fashions her granola from three types of crispy brick. Rolled oats and flakes of purple wheat (a unique, brightly colored cultivar which Suas sources from northern Canada) are steamed and pressed flat before drying. This pretreatment tenderizes the grains, prepping them for transformation into tiny, brittle shingles when toasted to drive off any lingering moisture. Thinly sliced almonds mirror the shape of the flattened grains but provide a sturdier snap derived from their natural concrete of oils bound in equal parts starch and protein. Puffed rice and kamut guard refreshing pockets of empty space in the tiny atriums contained within their thin, flash-set walls. This combination keeps our teeth guessing and our brains engaged.

For binding the nuts and grains together, Leong alloys maple syrup, brown sugar and butter with AP flour into a reinforced syrup. When baked, this mixture cascades molten treacle across the landscape, forming crunchy caverns, shelves and crusts studded with captured crispy bits.

The easiest way to make clustered granola is to smash fully baked and cooled slabs into smaller pieces. While efficient, this approach breaks and crumbles the delicate globes and flakes of nut and grain in jagged rifts over random fault lines.

To avoid setting off half of the textural fireworks before anyone can appreciate the show, Leong instead forms the clusters when the binder is 75 percent cooked and still pliable. This technique requires handling superheated maple lava, but it allows the clusters to break in tailored silhouettes around each grain or nut, preserving their explosive payload for the moment you bite down.

Co-owner Belinda Leong helps customers at b. Patisserie on California Street in San Francisco, Calif. on Saturday, March 10, 2018. Owners of the popular bakery are opening a shop in Seoul, South Korea next month.

Innovations in building materials made modern towers lighter, but savvy design and engineering were also key in sending the first skyscrapers upward. Leong and Suas push their carefully tested and refined recipes to greater heights by tinkering with the geometry of everything on their menu.

Brioche mousseline, a riff on the more conventional sandwich-style loaf, involves baking the buttery dough in an upright metal tube to form a silo of delicate crumb surrounded by brown walls of crispy crust. Mousseline molds range in shape, size and price point, from gleaming French-made gear to old coffee cans. These differences aren’t just aesthetic; the diameter and height of the container walls affect how a recipe will perform, just like the elevated bars and rings that facilitate an Olympic gymnastics routine.

Leong and Suas use a particularly narrow-diameter mousseline mold to give evaporating water in the dough one direction to expand when baked: up. In a wider mold, B. Patisserie’s tissue-soft brioche dough would collapse in the center as soon as the buoyant force of hot steam dissipates out of the oven. Instead, the narrow walls of their preferred molds conduct searing heat straight to the sides of the loaf as it climbs, cauterizing a rigid brown crust that provides enough structural support to keep the moist interior stretched tight as a drum.

Bostocks first evolved as a French toast-style method of repurposing day-old bread by rehydrating stale brioche in flavorful syrup before baking it back to life. While the B. Patisserie bakers make their brioche mousseline exclusively for this purpose, they still allow the baked loaves to age one day. Overnight, the starch lining the honeycomb walls of the crumb crystallizes, building up durable levees to withstand the flood of syrup to come.

Every morning, a B. Patisserie cook cuts each aged brioche loaf into 2-inch medallions to be dipped in a syrup flavored with passion fruit or orange blossom, depending on the season. Leong developed a dipping protocol that her staff practices with the reverence of Indiana Jones dipping a chalice at the end of “The Last Crusade.” She teaches her cooks to feel for the proper trickle of excess syrup filtering down through the bottom of each cake through gloved hands. Temperature plays a role in the process as well. Syrup that is too cold will lack the agility that it needs to enter and saturate every hidden corner of the medallion. Overheated syrup drips off before it can find a place to cling.

Leong seals each perfectly hydrated cylinder with a lid of almond cream. The piped cream forms an edible closure that keeps the interior moist while the outer ring of crust receives an extra spackling of blistering heat during a second turn through the oven.

Back when Earth was an embryonic chowder of simple chemicals and water, the first cells achieved true life in part by building fatty barriers to separate themselves from their environment. By enrobing itself in a thin layer of lipids, each individual cell gained the power to choose which water-borne nutrients, toxins, friends and foes would be welcomed or denied entry. Laminated pastries like croissants and B. Patisserie’s iconic kouign amann are possible because of a chemical pattern that facilitates life on Earth.

Water allows starch and gluten to snake around in any direction, forming some of the stickiest edible substances we have. Fat is a glossy force field through which water cannot pass, so any molecules trying to surf watery waves are also denied transit. When dispersed evenly throughout a doughy network of gluten and carbs, bakers use fat like a dimmer switch to slide along a continuum of dough textures from chewy to crumbly. Laminated doughs compress the chewy resilience of a lean, lightly sweetened dough into two-dimensional sheets, stacking layers of solid fat between them to provide a more dynamic form of tenderness.

The perfectly separated concentric circles seen in the dramatic cross sections of Instagram’s favorite croissants require extremely stiff dough. Tougher dough sheets prevent tears and flaws that would allow starch and protein in adjacent layers to high-five and glom together. Leong and Suas prefer a softer, more delicate dough, choosing to transmit visions of ecstatic texture into their customers’ minds through tongues rather than phones.

Working with B. Patisserie’s especially silky dough necessitates a tightrope act of butter management. Melted butter can escape into the pores of the dough and transform it into a crumbly block of pie crust, and butter that is too cold will shred tender dough, like an iceberg scraping the hull of a ship. To keep the butter within the correct, wire-thin temperature window, B. Patisserie bakers learn an intimate choreography that alternates between bear-hugging a parchment-swaddled batonof dough to warm it with gentle body heat and rushing it into refrigeration to rest and recuperate after each round of folding.

Physical agitation winds gluten like the springs of a clock to make dough firmer and more elastic. The repetitive folding and flattening required to make laminated layers excites these springs as though they were being kneaded, so Leong and Suas take care to start the process with dough even softer than their target texture.

Water embedded in each dough layer lies coiled and ready to expand with the heat of the oven, and butter gives each layer something to push off from without sticking to the layer below. B. Patisserie gives the expanding volcanoes of water a head start by carving out cavernous bubbles within the dough prior to baking, through the fermentative action of yeast.

After three rounds of folding, each dough slab receives a generous dusting of sugar. The sugared slabs are then cut into individual portions that B. Patisserie bakers fold into six-sided roses in stainless steel baking cups.

In the oven, the sugary crust drapes a lacquered cape across each petal of the blossoming pastry. A few rivulets of molten sugar trickle downward to escape the dry heat of oven air, leaving a spoonful of sticky syrup at the center of each pastry.

Crispy and chewy are an iconic culinary duo, but their chemical relationship is more toxic than the protagonists in a vampire-human love story. The corruptive influence of its moist interior will turn each pastry’s glassy, crispy shell back to caramel within hours.

This war of attrition means that B. Patisserie kouign amanns have a short shelf life, but during those precious few hours immediately after baking, they shimmer and stand tall like a Frank Gehry-designed croissant with a creme brulee skylight.